事实上，（）才是瓦特蒸汽机的动力。
A、蒸汽
B、热力
C、燃气
D、大气压
参考答案：D
关于宫内节育器的放置时间，下列哪项不妥()。
A．常规月经干净后3～7天
B．自然流产转经后
C．哺乳期闭经者，随时可放
D．足月产后3～6个月
E．人工流产同时可放
The passenger told the police he couldn't believe ______ at first. [ ]
A. what does the captain say
B. what the captain says
C. what did the captain say
D. what the captain said
